[Bug c++/14719] [tree-ssa] Excessive memory trashing on tree-ssa

["dnovillo at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From dnovillo at redhat dot com  2004-03-24 17:24 -------
Subject: Re:  New: [tree-ssa] Excessive memory trashing on
	tree-ssa

On Wed, 2004-03-24 at 12:16, giovannibajo at libero dot it wrote:
> This testcase kills tree-ssa with excessive memory trashing (as reported by 
> dnovillo, I didn't test it personally).
> 
> Otherwise, it would look great:
> 
> $ time g++-3.3 -c bitmachine.cc
> real    5m56.861s
> user    5m22.823s
> sys     0m3.514s
> RAM peak: 380MB
> 
> $ time g++-3.4 -c bitmachine.cc
> real    2m47.609s
> user    2m27.601s
> sys     0m2.682s
> RAM peak: 240MB
> 
> I'm linking this to PR 13776 which is a placeholder for compile time 
> regressions.
>
Well, I may have been too hasty in thinking it makes the compiler
thrash.  The system was pretty loaded at the time.  However, it does
kill the compiler, so it's worth having a look.  Here's the output I
got:

$ /usr/bin/time ~/perf/sbox/tree-ssa-branch/local.i686/inst.tobiano/bin/g++ -O2 -ftime-report bitmachine.cc  -fmem-report -w
Memory still allocated at the end of the compilation process
Size   Allocated        Used    Overhead
8           3044k       1804k         71k
16          2580k       1833k         40k
32            31M       8141k        379k
64            20M         17M        202k
128          644k        324k       5796
256         3292k        753k         25k
512         5564k       2474k         43k
1024        3488k       3488k         27k
2048         580k        578k       4640
4096         612k        612k       4896
8192         864k        864k       3456
16384       1296k       1296k       2592
32768        416k        416k        416
65536        128k        128k         64
262144        768k        768k         96
1048576       1024k       1024k         32
2097152       2048k       2048k         32
116          142M        127M       1284k
24            63M         28M        830k
36          7708k       3154k         82k
12            14M       7042k        269k
40            26M         16M        287k
Total        332M        225M       3566k

String pool
entries         100894
identifiers     100894 (100.00%)
slots           262144
bytes           15M (2473k overhead)
table size      1024k
coll/search     0.8489
ins/search      0.2790
bitmachine.cc:8308: internal compiler error: Aborted
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
Command exited with non-zero status 1
119.56user 30.66system 1:20:00elapsed 3%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (465933major+702807minor)pagefaults 0swaps






-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14719